BACKGROUND/AIM: Oval cell proliferation is known to occur in experimental models of hepatic regeneration and carcinogenesis. Recent studies have suggested that activation of progenitor cells, representing the human counterpart of oval cells, may play a role in hepatic diseases. Therefore, we evaluated putative progenitor cells in chronic viral hepatitis.
METHODS: Forty-one needle liver biopsy specimens from patients with chronic hepatitis B and 43 specimens from patients with chronic hepatitis C were examined histologically. The grade (histological activity index (HAI)) and stage (degree of fibrosis) were determined on routinely stained sections. The number of progenitor cells was assessed semiquantitatively on cytokeratin 7- (CK 7-) stained sections.
RESULTS: In both aetiological categories of chronic viral hepatitis, progenitor cell numbers were found to increase in parallel to the HAI, as well as to the stage of disease. Features suggestive of hepatocytic differentiation of progenitor cells were also noted on immunohistochemical stains for CK 7 and 'hepatocyte-specific' antigen.
CONCLUSIONS: In chronic hepatitis B and chronic hepatitis C, progenitor cell activation is correlated with the grade and stage of disease. Proliferating progenitor cells may play a role in hepatic regeneration occurring in this setting.